Isotopic niches of emperor and Adélie penguins in Adélie Land,Antarctica

The emperor and Adélie penguins are the only two species of penguins that co-occur at high-Antarctic latitudes. We first measured and compared their isotopic niches on the same year in Adélie Land in spring, when the two species co-exist. Emperor and Adélie penguins segregated by their blood isotopic signatures, with adult δ¹³C values (−24.5 ± 0.2 and −25.4 ± 0.2‰, respectively) suggesting that emperor penguins foraged in more neritic waters than Adélie penguins in spring. At that time, difference in their δ¹⁵N values (4.1‰, 12.0 ± 0.4 vs. 7.9 ± 0.1‰) encompassed more than one trophic level, indicating that emperor penguins preyed mainly upon fish (and squids), while Adélie penguins fed exclusively on euphausiids. Second, we compared the food of breeding adults and chicks. The isotopic signatures of adults and chicks of emperor penguins were not statistically different, but δ¹⁵N value of Adélie penguin chicks was higher than that of adults (10.2 ± 0.8 vs. 9.0 ± 0.2‰). The difference showed that adult Adélie penguins captured higher trophic level prey, i.e. higher-quality food, for their chicks. Third, the isotopic signatures of Adélie penguins breeding in Adélie Land showed that adults fed on Antarctic krill in oceanic waters in spring and shifted to neritic waters in summer where they preyed upon ice krill for themselves and upon fish and euphausiids for their chicks. A comparison of isotopic niches revealed large overlaps in both blood δ¹³C and δ¹⁵N values within the community of Antarctic seabirds and pinnipeds. The continuum in δ¹⁵N values nevertheless encompassed more than one trophic level (5.2‰) from Adélie penguin and crabeater seal to the Weddell seal. Such a broad continuum emphasizes the fact that all Antarctic seabirds and marine mammals feed on varying proportions of a few crustacean (euphausiids) and fish (Antarctic silverfish) species that dominate the intermediate trophic levels of the pelagic neritic and oceanic ecosystems.     

Application of standard statistical methods in the analysis of complex data generated from soil bioassays to assess the impacts of agrochemical-containing sludge amendments

The use of sludge as soil amendment is widely encouraged by its high contents in organic matter and plant nutrients. Nevertheless, agrochemicals potentially present in sludge could be harmful to terrestrial ecosystems. The present work aimed to apply standard statistical methods for suitable assessment of the ecotoxicological impacts of sludge amendments on soil, involving the following factors: the type of treated sludge, their application dose, and their contents in agrochemicals. Terrestrial Model Ecosystems were used to assess the effects of sludge amendments on endpoints from different trophic levels of the soil ecosystem, including an in vitro estrogenic bioassay on soil leachates. Here, we show the significant negative effects of the highest dose of sludge in most of the soil bioassays. Thermally dried sludge increased significantly the microbial activity leading to lower contamination of leachates with endocrine disrupting molecules. Agrochemicals contents of sludge have only significant impacts on increasing the delay of germination of plant seeds. Soil bioassays are thus complementary to sludge chemical analysis when the impacts of its application on soil should be assessed: significant negative impacts were related to the intrinsic composition of sludge rather than its agrochemicals contents. We conclude that standard statistical methods are relevant tools for the analysis of complex data generated from this type of experiment.     

Polymetallic pollution from abandoned mines in Mediterranean regions: a multidisciplinary approach to environmental risks

Regional Environmental Change - Abandoned mines are a recurrent problem for nearby communities in Mediterranean regions because mine tailings represent a major source of polymetallic contamination....     

Fine atmospheric particles emitted by industrial,traffic and urban sources in France: characterization and genotoxicity

Health risks associated with inhalation of fine particulate matter of 2.5 µm in diameter or smaller depend on their atmospheric levels and physicochemical properties. The relationships between chemical compositions and genotoxic activities of particles emitted by mineral industries, traffic and urban sources during summer and winter in the region of Provence-Alpes-Côte d'Azur (France) were investigated.

The fine particles were separated in respect to water-soluble (13 minerals and metals) and organic-extractable (16 polycyclic aromatic hydrocarbons) components that were quantified. The chromosome damaging properties of the hydrophilic and lipophilic extracts were assessed using the centromeric micronucleus assay on a human lung fibroblast cell line.

The composition of the fine particulate matter was variable and depended upon the sources and seasons. Both the hydrophilic and lipophilic extracts induced chromosome damage: (1) in hydrophilic extracts, Ca and Zn affected chromosome losses induction; (2) acenapthylene affected chromosome damage (breakages and losses) induction and naphthalene affected chromosome damage and losses induction in lipophilic extracts without metabolic activation; and (3) benzo[a]pyrene affected chromosome losses induction in lipophilic extracts with metabolic activation. Fine particulate matter arising from coal-fired power station, road traffic, and other urban sources were the most efficient to induce chromosome breakage.     

Ozone risk assessment for plants: central role of metabolism-dependent changes in reducing power

The combination of stomatal-dependent ozone flux and total ascorbate level is currently presented as a correct indicator for determining the degree of sensitivity of plants to ozone. However, the large changes in carbon metabolism could play a central role in the strategy of the foliar cells in response to chronic ozone exposure, participating in the supply of reducing power and carbon skeletons for repair and detoxification, and modifying the stomatal mode of functioning. To reinforce the accuracy of the definition of the threshold for ozone risk assessment, it is proposed to also consider the redox pool (NAD(P)H), the ratio between carboxylases and the water use efficiency as indicators of the differential ozone tolerance of plants.     

International cross-validation of a BOD5 surrogate

BOD5 dates back to 1912 when the Royal Commission decided to use the mean residence time of water in the rivers of England, 5 days, as a standard to measure the biochemical oxygen demand. Initially designed to protect the quality of river waters from extensive sewage discharge, the use of BOD5 has been quickly extended to waste water treatment plants (WWTPs) to monitor their efficiency on a daily basis. The measurement has been automatized but remains a tedious, time- and resource-consuming analysis. We have cross-validated a surrogate BOD5 method on two sites in France and in the USA with a total of 109 samples. This method uses a fluorescent redox indicator on a 96-well microplate to measure microbial catabolic activity for a large number of samples simultaneously. Three statistical tests were used to compare surrogate and reference methods and showed robust equivalence.     

Pesticide pressure and fish farming in barrage pond in northeastern France. Part III: how management can affect pesticide profiles in edible fish?

Purpose

The quality of fish produced in ponds needs to be ensured. Indeed, pond is often strongly connected to an agricultural watershed, and pesticides are a main health and environmental issue of concern. In this context, the purpose of this study is to highlight the management practices which could impact the pesticide contamination profiles in edible fish and to give recommendations for better practices.

Methods

A principal component analysis, coupled to a hierarchical cluster analysis, was performed to evaluate temporal evolution of contamination profiles and to assess variability among fish species and among sites according to watershed characteristics. The explicative variables correspond to muscular concentrations of pesticides (azoxystrobin, clomazone, diflufenican, carbendazim, isoproturon, metazachlor, napropamid) in three species of fish (Perca fluviatilis, Cyprinus carpio and Rutilus rutilus), caught in five ponds during two sampling campaigns. Management data are added variables in order to discuss about parameters suspected to be implicated in the contamination profiles recorded.

Results

This work shows that high amounts of pesticides applied, short crop rotation durations and bare soil practices led to contamination of sediments and fish and were associated to a “bad” management of watershed. Breeding fish that had low masses and establishing the fishing period at the end of winter seemed to be “bad” management of pond. Aggravating topological parameters were big watershed coupled to small pond and high proportions of sand soils in the watershed.

Conclusions

Reducing amounts of pesticide used (e.g. policy agency plans, farmer acceptance), favouring long-term rotations and inter-cultures, adapting pond creation and fish farming practices to watershed management and topography all could reduce pesticide levels in edible fish and contribute to a better sustainability of the extensive fish farming in pond.     

Diversity shift in bacterial phenol hydroxylases driven by alkyl-phenols in oil refinery wastewaters

Environmental Science and Pollution Research - Phenol hydroxylases (PHs) play a primary role in the bacterial degradation of phenol and alkylphenols. They are divided into two main classes,...